Extramedullary Plasmacytoma of the Oral Cavity in a Young Man: a Case Report.

Extramedullary plasmacytomas are rare solitary soft tissue tumors that arise from proliferations of malignant transformed monoclonal plasma cells and can be diagnosed through biopsy and histopathologic examination. These lesions are closely associated with multiple myelomas, which should be ruled out in all these cases by necessary laboratory and radiographic examinations. A 25-year-old man was referred to our clinic with a rapidly-growing painless lesion measuring about 2.5×3×3 cm in the palatal side of the left maxillary second and third molar teeth. A diagnosis of solitary plasmacytoma was made on the basis of clinical, radiographic, and histopathological findings. Early diagnosis of extramedullary plasmacytomas is of great importance. Radiotherapy is the common modality of treatment with or without adjuvant chemotherapy. Progression to multiple myeloma is possible; thus, close follow-up of the patient is essential after completion of the therapeutic procedure.


Introduction
Plasma cell tumors consist of extra medullary plasmacytoma (EMP), multiple myeloma (MM) and solitary bone plasmacytoma (SBP). Plasmacytoma is a plasma cell neoplasm of bone marrow that is in the end stage of B lymphocyte maturation. [1] It is a solitary tumor of neoplastic monoclonal plasma cells proliferation in either bone or soft tissue that is known as EMP. [2] Solitary plasmacytoma may be an isolated tumor in any region of body or the first manifestation of a subsequent MM.
EMP comprises up to 3% of all plasma cell tumors.
These tumors are more common in men, particularly in their sixth to eighth decades of life. [3] Extramedullary lesions may occur in the absence of bone involvement, especially in the head and neck region. [4] Approximately 90% of EMPs are found in the head and neck region. They commonly involve the nasal cavity, paranasal sinuses, tonsillar fossa, and oral cavity. [4] Yoshimura et al. reported 2 cases of plasmacytoma in the oral region. [5] The etiology of this disease is still unknown, but viruses, overdose irradiation, chronic stimulation, and gene disorders in the reticuloendothelial system have been suggested as the probable etiologic factors. [6] Some authors consider it to be unrelated to MM, even though both of them are similar in microscopic view. [7] Currently, the accepted criteria obtained by using MRI, flow cytometry, and polymerase chain reaction (PCR) include the solitary extramedullary mass of clonal plasma cells, bone marrow plasma cell infiltration (≤5.0% of all nucleated cells), absence of osteolytic lesions or other tissues involvement (no evidence of myeloma elsewhere), and absence or low level of serum or urinary monoclonal immunoglobulin. [4,8] Plasmacytomas can be graded as lesions of minimal to severe dysplasia. [1] In this article, we reported an EMP in an otherwise healthy young man.

Case Report
A 25-year-old man was referred to the Department of

Discussion
In addition to the division mentioned at the beginning of the article, plasmacytoma traditionally is divided into medullary and extramedullary types, which can be eith-  The rate of progression of EMP to MM is 15-20%. Harwood et al. reported the high rate of conversion to MM if EMP involved the underlying bone. [16] In some cases that were treated with radiation, 0.0-11% local recurrence was reported. In this situation, the recurrence in bone is concomitant with progression rate of multiple myeloma. [7] EMP is a rare lesion that comprises about 3% of all plasma cell neoplasms. So far, the majority of lesions have been seen in men of older ages; [3] while, our patient was a young man, which is a very rare case. Barros Management of EMP primarily involves local era-dication of the lesion. EMPs are highly-radiosensitive tumors. [17] Up to now, there is no established radiotherapy protocol for treatment of plasmacytoma. However, most studies accepted that 46 Gy is the best in local control with minimal toxicity. [18] Hence, our patient was treated by oncologists with approximately the same dose (40 Gy). For esthetic reasons, radical surgery should be avoided in management of solitary lesions in the head and neck region. When accessible, surgical removal may be considered for treatment of EMPs in other areas. If the surgical margins are also involved, the patient should receive adjuvant radiotherapy. [19]